Cementing Tool and Method for Using Same

ABSTRACT

A cementing tool is provided for use in cementing in casing or pipe in a well bore. The tool has an outer sleeve and an inner sleeve slidably disposed therein. The outer and inner sleeves can comprise aligned openings that allow cement to pass through once an opening seat disposed inside the inner sleeve slides down to expose the openings to the interior of the tool. The inner sleeve has convex protrusions extending outwardly from the inner sleeve and configured as circumferential seals to contact the inner wall of the outer sleeve in an interference fit. When the inner sleeve is moved downward to close off the openings in the outer sleeve, the interference seals prevent pressurized fracking fluid from exiting the tool through the outer sleeve openings.

TECHNICAL FIELD

The present disclosure is related to the field of tools for cementing in casing in a well bore, in particular, cementing tools for cementing in casing in wells that will be fracturized to stimulate production of hydrocarbons.

BACKGROUND

Well bores are often completed by injecting cement around the casing in the annulus space surrounding the casing in the well bore. The cement can hold the casing in place in the well bore, and can further create isolation in the well bore by preventing the passage of fluid between sections or stages within the well bore. As an example, the isolation can prevent the intermingling of water or gas that is present in one section with fluid hydrocarbons in another section. In wells where fracturizing or “fracking” is carried out to stimulate production of hydrocarbons, the isolation provided by cementing in the casing further assists in isolating the fracking operations to targeted production zones of the well.

It is known to use tools for cementing in the casing, which are placed in line with the casing when the casing is placed in the well bore. The prior art cementing tools can include movable sleeves that open ports extending through the sidewalls of the tool to allow cement injected into the casing to pass through the ports, and into the annulus of the well bore to cement in the casing. The ports can then be closed in the tool by a moving inner sleeve. Such tools comprise seals between the moving sleeves in the tool to close off the ports. The seals can include elastomer placed in grooves disposed around the sleeves to providing the sealing contact between the sleeves. The problem with the prior art cementing tools is that the seals used in them are not capable of withstanding the fluid pressures used or required in fracking operations once the casing is cemented in. Fracking fluid pressures as high as 15,000 pounds per square inch (“PSI”) may be required to properly fracture or stimulate a production zone in a well. As the cementing tool is placed in-line with the casing, the pressurized fracking fluid passes through the cementing tool to reach the desired production zone. Pressurized fracking fluid has been known to cause seal failure in the cementing tool, wherein fracking fluid can leak through the compromised seals of the cementing tool, thus reducing the volume and pressure of the fracking fluid that can be delivered to the production zone.

It is, therefore, desirable to provide a cementing tool that overcomes the shortcomings of prior art cementing tools.

SUMMARY

A cementing tool is provided for use in cementing in casing or pipe in a well bore, so as to provide isolation between sections or production zones within a well formation. In some embodiments, the tool can comprise an outer sleeve and inner sleeve slidably disposed therein. The outer and inner sleeves can comprise aligned openings that allow cement to pass through once an opening seat disposed inside the inner sleeve slides down to expose the openings to the interior of the tool. Once the cement has been placed around the casing or pipe, the inner sleeve can slide downwards, closing off the openings of the outer sleeve. The inner sleeve can comprise circumferential seals placed therearound such that when the inner sleeve is moved downward to a lower position to close off the outer sleeve openings, the seals can straddle these openings, thus closing off the openings. The seals themselves can comprise convex protrusions extending outwardly from the inner sleeve and configured to contact the inner wall of the outer sleeve in an interference fit. In this manner, the seals can seal off the outer sleeve openings from pressurized fracking fluid that is pumped through the tool and the casing, even at the high pressures used in fracking operations, which can reach as high as 15,000 PSI.

Broadly stated, in some embodiments, a cementing tool can be provided for cementing in a casing in well bore, the cementing tool comprising: a tubular outer sleeve defining a passageway therethrough, the outer sleeve comprising a first upper end configured to couple to a first pipe disposed thereabove, the outer sleeve further comprising at least one first opening disposed through a first sidewall of the outer sleeve; a tubular bottom subassembly operatively coupled to a first lower end disposed on the outer sleeve, the bottom subassembly configured to couple to a second pipe disposed therebelow; a tubular inner opening sleeve slidably disposed in the outer sleeve above the bottom subassembly; a tubular inner sleeve disposed in the outer sleeve above the inner opening sleeve, the inner sleeve further comprising at least one second opening disposed through a second sidewall of the inner sleeve, the inner sleeve comprising a first seal circumferentially disposed about the second sidewall above the at least one second opening, the inner sleeve comprising a second seal circumferentially disposed about the second sidewall above the first seal, the inner sleeve configured to move from a first upper position, wherein the at least one second opening is substantially aligned with the at least one first opening to provide communication between the at least one first opening and the passageway, to a first lower position wherein the first seal is disposed below the at least one first opening and the second seal is disposed above the at least one first opening to prevent communication between the at least one first opening and the passageway; and a tubular opening seat slidably disposed between the inner sleeve and the inner opening sleeve, the tubular opening seat configured to move from a second upper position, wherein the tubular opening seat prevents communication between the at least one first opening and the passageway, to a second lower position wherein the at least one first opening is in communication with the passageway.

Broadly stated, in some embodiments, one or both of the first and second seals can be integral to the inner sleeve.

Broadly stated, in some embodiments, one or both of the first and second seals further can comprise an interference fit between the inner sleeve and the outer sleeve.

Broadly stated, in some embodiments, one or both of the first and second seals can comprise a convex profile.

Broadly stated, in some embodiments, an outer diameter of one or both of the first and second seals can be greater than an inner diameter of the outer sleeve.

Broadly stated, in some embodiments, the outer diameter can be greater than the inner diameter by a range of 0.007 inches to 0.012 inches.

Broadly stated, in some embodiments, the convex profile can comprise a radius in the range of 0.4 inches to 0.6 inches.

Broadly stated, in some embodiments, the convex profile can comprise a width in the range of 0.3 inches to 0.4 inches.

Broadly stated, in some embodiments, a method can be provided for cementing in a casing in a well bore, the method comprising the steps of: providing the abovementioned cementing tool configured for cementing in the casing in the well bore; placing the cementing tool in a string of casing pipe and inserting the string into the well bore; shutting off the string below the cementing tool; moving the tubular opening seat from the second upper position to the second lower position; and injecting cementing into the string wherein cement flows from the passageway through the at least one first and second openings into an annular space surrounding the casing.

Broadly stated, in some embodiments, when a sufficient amount of cement has been placed in the annular space, the method can comprise the step of moving the inner sleeve from the first upper position to the first lower position.

BRIEF DESCRIPTION OF THE DRAWINGS:

FIG. 1 is a side elevation cut-away view depicting one embodiment of a cementing tool.

FIG. 2 is an exploded view depicting the metal on metal seal feature as shown as Detail A in FIG. 1.

FIG. 3 is an exploded view depicting the metal on metal seal feature as shown as Detail B in FIG. 1.

FIG. 4 is a side elevation cross-section view depicting one embodiment on an inner sleeve for use with the tool of FIG. 1.

FIG. 5 is a cross-section view depicting the metal seal shown as Detail C in FIG. 8.

FIG. 6 is a top plan view depicting a guide slot of the inner sleeve of FIG. 8.

FIG. 7 is a side cross-section view depicting one embodiment of the inner and outer sleeves of the tool of FIG. 1 when in a run-in and open position.

FIG. 8 is a side cross-section view depicting the inner and outer sleeves of FIG. 4 when in a closed position.

FIG. 9 is a side elevation view depicting a shut-off plug and baffle for use with the tool of FIG. 1.

FIG. 10 is a side elevation view depicting a closing plug for use with the tool of FIG. 1.

FIG. 11 is a side elevation cross-section view depicting the tool of FIG. 1 being run-in a well bore.

FIG. 12 is a side elevation cross-section view depicting the tool of FIG. 11 shown in an open position.

FIG. 13 is a side elevation cross-section view depicting the tool of FIG. 11 shown in a closed position.

DETAILED DESCRIPTION OF EMBODIMENTS:

Referring to FIG. 1, one embodiment of cementing tool 10 is shown. In some embodiments, tool 10 can comprise tubular housing or outer sleeve 12 threadably coupled to tubular bottom subassembly or “sub” 14 via threaded end 15 threaded into threaded opening 17 to define passageway 20 extending from inlet coupling 16 to outlet coupling 18. Inlet coupling 16 can comprise a threaded box end for threadably coupling to a section of casing disposed above tool 10. Outlet coupling 18 can comprise a threaded pin end for threadably coupling to another section of casing disposed below tool 10. In some embodiments, tool 10 can comprise tubular inner opening sleeve 30 threaded into threaded opening 31 disposed on the upper end of bottom sub 14.

In some embodiments, tool 10 can comprise inner sleeve 22 slidably disposed within outer sleeve 12. Inner sleeve 22 can be initially positioned within outer sleeve 12 with a plurality of shear pins 27 extending from closing seat 24 of inner sleeve 22 into corresponding openings disposed on the inner wall of outer sleeve 12 such that openings 36 extending through the sidewall of inner sleeve 22 are substantially aligned with openings 34 extending through the sidewall of outer sleeve 12. Each of outer sleeve 12 and inner sleeve 22 can comprise a plurality of openings 34 and 36, respectively, extending through the sidewalls thereof. In some embodiments, inner sleeve 22 can comprise a plurality of vertical slots 60 disposed on the outer sidewall thereof, wherein slots 60 can be configured to receive setscrews 62 extending inwardly from the inner sidewall of outer sleeve 12. The combination of slots 60 and setscrews 62 can limit the amount of travel inner sleeve 22 can move within outer sleeve 12 in a vertical direction, and can further prevent inner sleeve 22 from twisting within inner sleeve 12, thus keeping openings 34 and 36 substantially aligned with each other. The length, depth and number of slots 60 can be chosen or selected as a matter of design considerations arising from the size and diameter of tool 10, the choice or selection of which is well known or obvious to those skilled in the art. In a representative embodiment, each of outer and inner sleeves 12 and 22 can comprise six openings 34 and 36, respectively, disposed about the circumferences thereof, spaced substantially equidistant apart, and can further comprise six slots 60 and six setscrews 62 disposed about the circumferences of inner and outer sleeves 22 and 12, respectively, spaced substantially equidistant apart.

In some embodiments, tool 10 can comprise tubular opening seat 32 slidably disposed within inner sleeve 22 and inner opening sleeve 30. In an initial position, opening seat 32 can be positioned in an upper position within inner sleeve 22 and inner opening sleeve 30 wherein communication between passageway 20 and openings 34 and 36 is blocked.

Referring to FIGS. 1, 2 and 3, tool 10 can comprise seals 26 and 28 disposed around the circumference of inner sleeve 22. Seal 26 can be disposed above slot 60, and seal 28 can be disposed below slot 60. In some embodiments, each of seals 26 and 28 can comprise a convex-shaped protrusion extending from outer sidewall 21 of inner sleeve 22 such that seals 26 and 28 can contact inner sidewall 23 of outer sleeve 12 in an interference fit. In some embodiments, the outer diameter of inner sleeve 22 as defined by the outer edge of seals 26 and 28 can be 0.007 to 0.012 inches greater than the inner diameter of outer sleeve 12 as defined by inner sidewalls 23.

Referring to FIG. 4, a cross-section view of one embodiment of inner sleeve 22 is shown. In some embodiments, inner sleeve 22 can comprise grooves 64 and 66 configured for receiving elastomer o-rings seals to prevent fluids from entering into an annular space located between inner opening sleeve 30 and outer sleeve 12 which would prevent inner sleeve 22 from fully descending within outer sleeve 12 to fully close off and seal openings 34. Inner sleeve 22 can further comprise threaded opening 29 configured for threadably receiving closing seat 24.

Referring to FIG. 5, a cross-section view of seal 26 or 28 is shown. In some embodiments, seal 26 or 28 can comprise a convex protrusion extending from outer sidewall 21 of inner sleeve 22. In some embodiments, the convex protrusion can comprise a radius R in the range of 0.4 inches to 0.6 inches. In a representative embodiment, radius R can be 0.5 inches. In some embodiments, the convex protrusion can comprise a width W in the range of 0.3 inches to 0.4 inches. In a representative embodiment, width W can range from 0.341 inches to 0.347 inches.

Referring to FIG. 6, one embodiment of slot 60 is shown. The length of slot 60 can be selected in accordance with the diameter of tool 10. When tool 10 is configured for use with a 4½ inch casing, slot 60 can be milled to be 2.00 inches long and 0.562 inches wide, to a depth of 0.090 inches. When tool 10 is configured for use with a 9⅝ inch casing, slot 60 can be milled to be 2.50 inches long and 0.562 inches wide, to a depth of 0.090 inches.

Referring to FIGS. 7 and 8, representations of outer and inner sleeves 12 and 22 are shown. When inner sleeve 22 is in an upper position within outer sleeve 12, both of seals 26 and 28 are positioned above opening 34. When inner sleeve 22 is in a lower position within outer sleeve 12, seal 26 is positioned above opening 34 whereas seal 28 is positioned below opening 34 thus enclosing opening 34 between seals 26 and 28 and, thus, preventing any communication between opening 34 and passageway 20. The diameter of openings 34 and 36 can be chosen or selected in accordance with design considerations arising from the diameter of tool 10, the choice or selection of which is well known or obvious to those skilled in the art. When tool 10 is configured for use with a 4½ inch casing, openings 34 and 36 can be 0.81 inches in diameter. When tool 10 is configured for use with a 9⅝ inch casing, openings 34 and 36 can be 1.13 inches in diameter.

Referring to FIG. 9, one embodiment of a shut off plug and baffle for use with tool 10 is shown, as shown in FIGS. 11, 12 and 13 and discussed in further detail below. In some embodiments, baffle 38 can comprise a tubular subassembly that can be placed between adjoining sections of casing 8 joined together with coupler 9, as shown in FIGS. 11 to 13. Baffle 38 can further comprise frustoconical-shaped seat 39 configured to receive frustoconical-shaped plug 48 disposed on a lower end of shut off plug 40. Plug 40 can further comprise cup 42 connected to plug 48 via plug shaft 46. Plug 40 can further comprise a plurality of circumferential fins 44 disposed around shaft 46.

Referring to FIG. 10, one embodiment of closing plug 50 for use with tool 10 is shown, as shown in FIG. 13 and discussed in further detail below. In some embodiments, plug 50 can comprise cup 52 connected to frustoconical-shaped plug 58 via plug shaft 56. Plug 50 can further comprise a plurality of circumferential fins 54 disposed around shaft 56. Plug 58 can be configured to seat in frustoconical-shaped seat 25 disposed in closing seat 24.

Referring to FIG. 11, tool 10 is shown coupled between sections of casing 8 via coupling 9 when the casing is being run into a well bore. In this configuration, opening seat 32 is in an upper position wherein openings 36 are closed off from passageway 20. Once the casing has been run in to its position within the well bore, tool 10 can then be operated to cement in the casing in the region surrounding tool 10.

Referring to FIG. 12, shut off plug 40 is run down casing 8 followed by displacement fluid, such as water, drilling mud, brine water or other like fluid as well known to those skilled in the art, to push shut off plug 40 down the casing. Fins 44 and cup 42 help keep shut off plug 40 centered and stable in the casing as it makes its way down the casing, and through tool 10 to seat on baffle 38 where plug 48 seats on seat 39. Once shut off plug 40 is seated, cement can then be injected into casing 8 and down to tool 10 located above shut off plug 40. The hydraulic pressure of the cement can then also cause opening seat 32 to travel downward, sliding into inner opening sleeve 30, to reveal openings 36, which can be substantially aligned with openings 34. Once opening seat 32 is pushed downwards to a lower position where opening seat 32 is in contact with inner opening sleeve 30, the pressurized cement can then exit tool 10 by passing through openings 36 and 34, and into the annular space surrounding tool 10 and the casing in the well bore, thus cementing in the casing in the well bore. When a sufficient amount of cement has been placed, closing plug 50 can be run down the casing with displacement fluid until it contacts closing seat 24. Fins 54 and cup 52 help keep closing plug 50 centered and stable as it makes its way down the casing, and any tools placed in line with the casing above tool 10.

Referring to FIG. 13, closing plug 50 is shown seated in closing seat 24 wherein plug 58 is firmly seated in seat 25. The hydraulic pressure of the cement/fluid pushing downward on plug 50 can shear shear pins 27, thus allowing inner sleeve 22 to move downward, guided by setscrews 62 extending into slots 60, and then close off openings 34 as seal 28 slides downward below openings 34 when inner sleeve 22 reaches a lower position where inner sleeve 22 contacts bottom sub 14.

In one test that was conducted on a tool configured as a 5½″, 26 pound, P-110 Hydraulic Ball Seal Stage Cementing tool, the following steps and results were carried out and observed:

-   -   1. The inner sleeve was installed into housing with a hydraulic         press at 18,860 lbs of force.     -   2. The opening seat assembly and bottom sub was installed into         the tool.     -   3. The test caps were installed on both ends of the tool.     -   4. Pressure was applied and the opening seat opened at 4000 PSI         with 7⅜″ (0.268) brass pins.     -   5. The top test cap was removed to install the closing plug was         installed, the top test cap was then reinstalled.     -   6. Pressure was applied and the inner sleeve started to close at         800 PSI, the pressure dropped to 400 PSI as the tool closed, but         came back to 800 PSI at complete close, with the pressure being         raised to 3200 PSI and held at this pressure for 3 minutes.     -   7. The top test cap was removed to remove the closing plug, with         the top test cap then being reinstalled.     -   8. Pressure was applied to the tool up to 15,000 PSI for 22         cycles at 10 minutes per each cycle.     -   9. No leaks were observed in the tool.

In another test that was conducted on a tool configured as a 7″, 41 pound, P-110 Hydraulic Ball Seal Stage Cementing tool, the following steps and results were carried out and observed:

-   -   1. The inner sleeve was installed into housing with a hydraulic         press at 25,380 lbs of force.     -   2. The opening seat assembly and bottom sub was installed into         the tool.     -   3. The test caps were installed on both ends of the tool.     -   4. Pressure was applied and the opening seat opened at 3000 PSI         with 7⅜″ (0.265) brass pins.     -   5. The top test cap was removed to install the closing plug was         installed, the top test cap was then reinstalled.     -   6. Pressure was applied and the inner sleeve started to close at         500 PSI, the tool was closed at 800 PSI, with the pressure being         raised to 3200 PSI and held at this pressure for 2 minutes.     -   7. The top test cap was removed to remove the closing plug, with         the top test cap then being reinstalled.     -   8. Pressure was applied to the tool up to 15,000 PSI for 22         cycles at 10 minutes per each cycle.     -   9. No leaks were observed in the tool

In the foregoing disclosure, the description and operation of tool 10 has been provided. While the placement and operation of a single tool 10 to cement in casing in a well bore has been discussed, it should also be well known or obvious to those skilled in the art that two or more tools 10 can be placed in line with a casing placed in a well bore to permit the cementing in of the casing at various locations or stages to provide multiple, cemented-in production zones in the formation. This can take place in vertically-drilled wells, or in diagonally-drilled or horizontally-drilled wells.

Although a few embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications can be made to these embodiments without changing or departing from their scope, intent or functionality. The terms and expressions used in the preceding specification have been used herein as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding equivalents of the features shown and described or portions thereof, it being recognized that the invention is defined and limited only by the claims that follow. 

What is claimed is:
 1. A cementing tool for cementing in a casing in a well bore, the cementing tool comprising: a) a tubular outer sleeve defining a passageway therethrough, the outer sleeve comprising a first upper end configured to couple to a first pipe disposed thereabove, the outer sleeve further comprising at least one first opening disposed through a first sidewall of the outer sleeve; b) a tubular bottom subassembly operatively coupled to a first lower end disposed on the outer sleeve, the bottom subassembly configured to couple to a second pipe disposed therebelow; c) a tubular inner opening sleeve slidably disposed in the outer sleeve above the bottom subassembly; d) a tubular inner sleeve disposed in the outer sleeve above the inner opening sleeve, the inner sleeve further comprising at least one second opening disposed through a second sidewall of the inner sleeve, the inner sleeve comprising a first seal circumferentially disposed about the second sidewall above the at least one second opening, the inner sleeve comprising a second seal circumferentially disposed about the second sidewall above the first seal, the inner sleeve configured to move from a first upper position, wherein the at least one second opening is substantially aligned with the at one least first opening to provide communication between the at least one first opening and the passageway, to a first lower position wherein the first seal is disposed below the at one least first opening and the second seal is disposed above the at least one first opening to prevent communication between the at least one first opening and the passageway; and e) a tubular opening seat slidably disposed between the inner sleeve and the inner opening sleeve, the tubular opening seat configured to move from a second upper position, wherein the opening seat prevents communication between the at least one first opening and the passageway, to a second lower position wherein the at least one first opening is in communication with the passageway.
 2. The cementing tool as set forth in claim 1, wherein one or both of the first and second seals are integral to the inner sleeve.
 3. The cementing tool as set forth in claim 1, wherein one or both of the first and second seals further comprises an interference fit between the inner sleeve and the outer sleeve.
 4. The cementing tool as set forth in claim 3, wherein one or both of the first and second seals comprises a convex profile.
 5. The cementing tool as set forth in claim 4, wherein an outer diameter of one or both of the first and second seals is greater than an inner diameter of the outer sleeve.
 6. The cementing tool as set forth in claim 5, wherein the outer diameter is greater than the inner diameter by a range of 0.007 inches to 0.012 inches.
 7. The cementing tool as set forth in claim 4, wherein the convex profile comprises a radius in the range of 0.4 inches to 0.6 inches.
 8. The cementing tool as set forth in claim 4, wherein the convex profile comprises a width in the range of 0.3 inches to 0.4 inches.
 9. A method for cementing in a casing in a well bore, the method comprising the steps of: a) providing a cementing tool configured for cementing in the casing in the well bore, the cementing tool comprising: i) a tubular outer sleeve defining a passageway therethrough, the outer sleeve comprising a first upper end configured to couple to a first pipe disposed thereabove, the outer sleeve further comprising at least one first opening disposed through a first sidewall of the outer sleeve, ii) a tubular bottom subassembly operatively coupled to a first lower end disposed on the outer sleeve, the bottom subassembly configured to couple to a second pipe disposed therebelow, iii) a tubular inner opening sleeve slidably disposed in the outer sleeve above the bottom subassembly, iv) a tubular inner sleeve disposed in the outer sleeve above the inner opening sleeve, the inner sleeve further comprising at least one second opening disposed through a second sidewall of the inner sleeve, the inner sleeve comprising a first seal circumferentially disposed about the second sidewall above the at least one second opening, the inner sleeve comprising a second seal circumferentially disposed about the second sidewall above the first seal, the inner sleeve configured to move from a first upper position, wherein the at least one second opening is substantially aligned with the at least one first opening to provide communication between the at least one first opening and the passageway, to a first lower position wherein the first seal is disposed below the at least one first opening and the second seal is disposed above the at least one first opening to prevent communication between the at least one first opening and the passageway, and v) a tubular opening seat slidably disposed between the inner sleeve and the inner opening sleeve, the tubular opening seat configured to move from a second upper position, wherein the tubular opening seat prevents communication between the at least one first opening and the passageway, to a second lower position wherein the at least one first opening is in communication with the passageway; b) placing the cementing tool in a string of casing pipe and inserting the string into the well bore; c) shutting off the string below the cementing tool; d) moving the tubular opening seat from the second upper position to the second lower position; and e) injecting cementing into the string wherein cement flows from the passageway through the at least one first and second openings into an annular space surrounding the casing.
 10. The method as set forth in claim 9, when a sufficient amount of cement has been placed in the annular space, moving the inner sleeve from the first upper position to the first lower position.
 11. The method as set forth in claim 9, wherein one or both of the first and second seals are integral to the inner sleeve.
 12. The method as set forth in claim 9, wherein one or both of the first and second seals further comprises an interference fit between the inner sleeve and the outer sleeve.
 13. The method as set forth in claim 12, wherein one or both of the first and second seals comprises a convex profile.
 14. The method as set forth in claim 13, wherein an outer diameter of one or both of the first and second seals is greater than an inner diameter of the outer sleeve.
 15. The method as set forth in claim 14, wherein the outer diameter is greater than the inner diameter by a range of 0.007 inches to 0.012 inches.
 16. The method as set forth in claim 13, wherein the convex profile comprises a radius in the range of 0.4 inches to 0.6 inches.
 17. The method as set forth in claim 13, wherein the convex profile comprises a width in the range of 0.3 inches to 0.4 inches. 